Immunotherapy is the treatment of disease by inducing, enhancing, or suppressing the immune response. Immunotherapy can stimulate the patient's own immune system to attack cancer cells. Cancer immunotherapy usually has fewer side effects than traditional cancer therapies, such as chemotherapy and radiation therapy. Anti-inflammatory immunotherapy can down-regulate the patient's immune system for treating autoimmune diseases and graft-versus-host disease (GvHD). What is needed are improved methods for delivering immunomodulatory molecules to cells and tissues of the body.